1. Field of the Invention
The present invention relates to a mold for manufacturing a finely meshed plastic filter.
2. Description of the Related Art
To integrally mold a filter having a narrow-pitched mesh structure through injection molding, the gas or air must be completely removed from inside the mold. For the mold core and cavity to achieve this purpose, a porous sintered metal has been conventionally used in which gaps are formed between metal particles. The air inside the mold was externally released from between the metal particles.
On the other hand, the mold disclosed in Japanese Patent Application Laid-Open Publication No. 1998-193405 is formed with air bleeding guide paths communicating with the cavity.
The drawback to providing the core or cavity with a porous sintered metal is that the porous surface will gradually become blocked with resin, eventually resulting in failure to bleed the air. Moreover, the air bleeding guide paths of the aforementioned patent document are cumbersome to manufacture and likely permit entry of resin therein. And, in any case, the manufacture of the conventional molds has been cumbersome, resulting in a high mold cost.